Photoflash lamp



R. LE R. KREIDLER 7 l 2,201,294

PHOTOFLASH LAMP Filed Sept. 25, 19:7

ATTORNEY Patented May 21, 1940 PATENT OFFICE 4 rno'rormsn LAMP Raymond Le Roy Kreidler, Bloomfield, N. 1., assignor' to Westinghouse Electric & Manufacturing Company, East Pittsburgh, pcration of Pennsylvania 1 Pa... a cor- Application September 23, 1987, Serial No. 165,348

4 Claims. (01. 67-31) This invention relates to flashlight lamps and particularly to what are known in the art as photoflash lamps of the type which give a momentary flash of intense light for the taking of photographic exposures. V Lamps of this general type are known to the art in which the actinic eflfect is obtained by theuse of an oxidizable material such as magnesium, aluminum or alloys of magnesium with aluminum- Such material is usually in the form of foil, wire, or ribbons, disposed in a transparent vitreous envelope containing an oxygenic atmosphere which, upon the passage of electrical current through an igniter element, causes combustion of the oxidizable material in the presence of oxygen, giving a momentary actinic effect.

The successful operation of photoflash lamps depends on the fact that the foil, wire or ribbon, must be of suflicient physical dimensions so that it can be readily ignited and then burn'ed with sumcient rapidityto give ofi suflicient light to be useful in the taking of snapshot photographs.

Fabrication of the oxidizable material has heretofore been accomplished only with considerable difliculty. In the manufacture of aluminum foil, which is one of the most common oxidizable materials at present employed, the general practice is to use a beating process similar to that used in the beating of gold leaf since aluminum foil to be combustible must be extremely thin. This is not only a rather costly process but the thickness of the completed foil is by no means uniform, which thus aflects the rapidity of combustion and, notonly the intensity of the emitted light, but also the period of flashing, which latter should, for best results, occur simultaneously with complete opening of the camera shutter.

Also, due to the physical characteristics of pure aluminum and magnesium, it has been impractical to draw wire from these metals to a size fine enough for satisfactory performance in photoflash lamps inasmuch as it must be of a diameter not substantially greater than mil.

Owing to the above noted defects, alloys of magnesium and aluminum have better working characteristics than pure magnesium and better burning qualities than pure aluminum, and, consequently, such alloys have been employed in photoiiash lamps in the form of wire. However,

lamps using such alloy in wire form have been very erratic in performance due to a non-uniformity of combustion.

Also the present practice employed in drawing wire of these alloys consists in making small drafts and in heating the material and die to a temperature ranging from approximately 850 C. to 450 C. during the drawing operation. Again, however, this is a costly process.

It is accordingly an object of the present invention to provide an oxidizabie material which is readily and uniformly combustible in an oxygenic atmosphere and which possesses a high actinic characteristic together with a very rapid combustion rate.

Another object of the present invention is'the provision of a photoflash lamp containing an oxidizable material which is readily and uniformly combustible in an oxygenic atmosphere and which possesses a high actinic characteristic together with a rapid combustion rate.

Another object of the present invention is the provision of photoflash lamp material which burns rapidly and uniformly, thus giving maximum actinic effect in a very short period of time.

Another object of the present invention is the provision of an onidizable material for photofiash lamps which can be very readily cold-worked.

Still further objects of the present invention will become obvious to those skilled in the art by reference to the following more detailed description, taken in conjunction with the accompanying drawing in which: 1

Fig. 1 is an-elevational view of a photoflash lamp constructedin accordance with the teachings of thepresent invention wherein the combustible material is in the form of foil, and

Fig.2 is an elevational view of a photoflash lamp constructed in accordance with the prescut invention in which the combustible material is in the form of wire.

Referring now to the drawing in detail, a photoflash lamp is shown in Fig. 1 comprising an evacuated envelope 5 to which is attached a suitable base 6 for engagement with the customary socket. The lamp isprovided with an oxygenic atmosphere and a combustible material in the form of foil 1 is disposed therein, which foil consists of an allow as hereinafter more fully described, either alone orin combination with foil of a pure readily combustible material.

The lamp is also provided with an igniter element 8 suspended between the leading-in con- -ductors extending from the base 6 so that upon The construction shown, in Fig. 2 is identical to that just described with the exception that the readily combustible material 1 in this modificationis in wire form, which wire constitutes an alloy either alone or combined with pure aluminum or magnesium wire, as hereinafter more fully described. J

The aforenoted inherent difiiculties found in foil and wire at present utilized as photoflash lamp material are overcome in the photoflash lamp according to: the present invention by utilizing an alloy of magnesium) and manganese or an alloy of magnesium, manganese and tin. Ex-

tensive tests have shown that magnesium alloys containing low percentages of manganese can be proves the photoflash lamp for photographic purposes.

The material consisting of an alloy of magnesium containing manganese in the proportions above noted with or without the addition of tin may be employed in aphotoflash lamp in the form of foil, wire or ribbon, either alone or in combination with other material such as pure aluminum or pure magnesium foil. In either event, the actinic effect-as well as the rapidity of combustion is greatly increased which results in an improved photoflash lamp.

It has also been noted that while the magnesium ,alloy containing the manganese may, as above noted, be coldworked, slight variations in the uniformityof thickness thereof apparently have no deleterious effect on the quality of the actinic light produced nor in the rate of combustion, nor does such alloy, whether in the form of wire or foil, have to be as thin as in the 1 case of aluminum foil or magnesium wire.

bustion of the materialupon the passage of electrical cu rent through the lamp. A lamp of this type is shown and described in my joint application, Serial No. 162,116 filed Sept. 2, 1937, and

vention. I

In view of the foregoing it becomes obvious to those skilled in the art that I have provided a photoflash lamp containing an oxidizable material having a high rate of combustion when employed in a photoflash lamp either in the form of foil, wire or ribbon and when utilized either alone or in combination with other combustible materials in thepres'ence of an oxygenic atmosphere. 7

Although I have described one specific embodiment of my present invention, I do not desire to be limited thereto, as various other modifications of the same may be made without departing from the spirit and scope of the appended claims. 1

I claim: I 1. A photoflash lamp comprising a sealed container, an oxygenic atmosphere within said container, an oxidizable material in said container which is readily combustible with oxygen and comprising an alloy including magnesium and manganese, said alloy having a manganese content ranging from 0.5% to 10% with magnesium the major portion of the balance, and an igniter assigned to the same assignee 'as the present inin said container for initiating combustion of said material.

2. A photoflash lamp comprising a sealed container. an oxygenic atmosphere within said container, an oxidizable material which is readily combustible with oxygen and comprising an alloy including magnesium and manganese in proportionsv ranging from 83% to 96.5% of the former and 0.5% to 10% of the latter disposed in said container together with a quantity of substantially pure aluminum, and an igniter in said container for initiating combustion of said material.

3. A photoflash lamp comprising a sealed container, an oxygenic atmosphere within said container, an oxidizable material which is readily combustible with oxygen and comprising an alloy including magnesium and manganese in pro- 7 portions ranging from 83% to 96.5% former and 0.5% to 10% of the latter disposed in said container together with a. quantity of substantially pure magnesium, and anigniter in said container for initiating combustion of said material. I

4. A photoflash lamp comprising a sealed con-' of thetainer, an 'oxygenic atmosphere within-said container, an oxidizable material in said container which is readily combustible with oxygen and comprising an alloy including magnesium, manganese and tin, said alloy having a manganese content ranging from 0.5% to 10% and a tin content ranging from 3% to 7% with the balance proportionately magnesium, and an igniter in said container forinitiating combustion of said material.

RAYMOND LE ROY KREIDLER. 

